Three retired judges will join a task force and review 3,000 past arrests as part of a probe involving 14 San Francisco city police officers linked to racist and homophobic text messages, a prosecutor said Thursday.

Former state Supreme Court Justice Cruz Reynoso, Judge Ladoris Cordell and Judge Dickran Tevrizian have experience in civil rights and criminal justice reform and will determine if bias led to wrongful prosecutions, District Attorney George Gascón said in a statement.

If one person was wrongly imprisoned because of bias by the officers, "that's one too many," Gascón said.

The texts included slurs against blacks, Mexicans, Filipinos and gays, and feature officers and civilians repeatedly using the phrase "white power."

The texts were discovered by federal authorities in a probe of former San Francisco police Sgt. Ian Furminger, who was recently convicted of corruption. The names of the officers under investigation have not been released.

Gascón said the retired judges will also evaluate whether there is a deeper culture of bias at the Police Department.

"If we want the public to trust law enforcement we need a culture of justice, transparency and accountability - not bias, secrecy and impunity," Gascón said. "The actions of a few have undermined the public's faith in the police officers."

To ensure their independence, the judges are from outside San Francisco and will not be paid. They are expected to complete their investigation by the end of the year.

Last month Police Chief Greg Suhr said he had asked a police oversight committee to approve firing seven officers. Six others face disciplinary actions that include reassignment to positions that don't have contact with the public. Another officer tied to the investigation has resigned.